School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand.
School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand.
Biomolecules. 2017 Apr 11;7(2):37. doi: 10.3390/biom7020037.
Amyloid fibrils are a class of insoluble protein nanofibers that are formed via the self-assembly of a wide range of peptides and proteins. They are increasingly exploited for a broad range of applications in bionanotechnology, such as biosensing and drug delivery, as nanowires, hydrogels, and thin films. Amyloid fibrils have been prepared from many proteins, but there has been no definitive characterization of amyloid fibrils from hemoglobin to date. Here, nanofiber formation was carried out under denaturing conditions using solutions of apo-hemoglobin extracted from bovine waste blood. A characteristic amyloid fibril morphology was confirmed by transmission electron microscopy (TEM) and atomic force microscopy (AFM), with mean fibril dimensions of approximately 5 nm diameter and up to several microns in length. The thioflavin T assay confirmed the presence of β-sheet structures in apo-hemoglobin fibrils, and X-ray fiber diffraction showed the characteristic amyloid cross-β quaternary structure. Apo-hemoglobin nanofibers demonstrated high stability over a range of temperatures (-20 to 80 °C) and pHs (2-10), and were stable in the presence of organic solvents and trypsin, confirming their potential as nanomaterials with versatile applications. This study conclusively demonstrates the formation of amyloid fibrils from hemoglobin for the first time, and also introduces a cost-effective method for amyloid fibril manufacture using meat industry by-products.
淀粉样纤维是一类不溶性蛋白质纳米纤维，通过广泛的肽和蛋白质的自组装形成。它们越来越多地被用于生物纳米技术的广泛应用，如生物传感和药物输送，作为纳米线、水凝胶和薄膜。已经从许多蛋白质中制备了淀粉样纤维，但迄今为止，尚未对血红蛋白来源的淀粉样纤维进行明确的特征描述。在这里，使用从牛废血中提取的脱辅基血红蛋白溶液，在变性条件下进行了纳米纤维的形成。通过透射电子显微镜（TEM）和原子力显微镜（AFM）确认了特征性的淀粉样纤维形态，平均纤维尺寸约为 5nm 直径，长达数微米。噻唑蓝 T 试验证实了脱辅基血红蛋白纤维中存在β-折叠结构，X 射线纤维衍射显示了特征性的淀粉样交叉-β四级结构。脱辅基血红蛋白纳米纤维在 -20 至 80°C 的温度范围和 2-10 的 pH 值下表现出高稳定性，并且在有机溶剂和胰蛋白酶存在下稳定，这证实了它们作为具有多种应用的纳米材料的潜力。本研究首次从血红蛋白中成功地形成了淀粉样纤维，并引入了一种使用肉类工业副产品制造淀粉样纤维的经济有效的方法。
